Press the Load button and wait until Buckminster has resolved all the dependencies (go and fetch a coffee, or two, or three).

When the dependencies have been resolved properly hit the 'Finish' button:

Finally open the Preferences (Window->Preferences) and go to the "Target Platform" page. Edit the active target platform and remove the location (not the target platform definition as a whole!) that points to the running installation. Now you're done.

Update the Workspace

You can update your development workspace by re-importing the local.mpec (right-click + Buckminster + Import...). Then the whole workspace and the target platform are updated.

Note, that re-importing does only add new source projects but doesn't update existing source projects from the Git repository. Use the 'Pull' command of EGit for this purpose!